A stilted, mannered comedy that barely runs an hour and a half and still manages to feel three times as long as Avengers: Infinity War, Birthmarked might be the worst thing you see this year, if you’re foolhardy enough to buy a ticket.

Following up his slow but watchable drama Whitewash – the one in which Thomas Haden Church played a drunk snowplow operator who accidentally kills someone on the job – Quebec director Emanuel Hoss-Desmarais changes gears entirely for this one.

Chipper narration by Fionnula Flanagan places us at an arch distance from the movie’s protagonists, Catherine (Toni Collette) and Ben (Matthew Goode), American behavioural scientists who meet as colleagues, fall in love and become obsessed with the idea of proving nurture over nature.

In the late 70s they launch their grand experiment, moving to a remote cabin to rear their own child and two adopted children in direct opposition to their genetic inclinations. Their son – a child of scientists! – will be raised as an artist, the daughter of idiots as an intellectual, and the son of a violent couple as a pacifist.

Most of the film takes place a decade into the experiment, with the kids as maladjusted weirdos and the parents slowly turning on one another out of frustration and boredom. And trust me on this: whatever that synopsis led you to imagine, it’s funnier, scarier or more moving than Birthmarked.

Seriously. Hoss-Desmarais and screenwriter Marc Tulin take a premise worthy of Wes Anderson (or Robert Altman, or Paul Thomas Anderson, or Mike Leigh) and slowly, methodically choke every last glimmer of life out of it.

Collette and Goode are terrific actors, but they can’t do anything with their paper-thin characterizations of OCD focus and repressed sexual deviancy, respectively; the kids have nothing to do but sulk or yell, and a subplot featuring the wonderful Irish actor Michael Smiley as the debauched millionaire fronting the whole experiment is so half-assed that I wound up offended on Smiley’s behalf.

It’s arriving in theatres two weeks ahead of Hereditary, a far better film that also stars Collette as the matriarch of a disintegrating family, and I’m sure that’s not a coincidence. Don’t fall for it.